National Junior Classical League:
http://www.njcl.org/

Texas State Junior Classical League:
http://www.tsjcl.org/

Perseus Digital Library:
http://www.perseus.tufts.edu/

Ancient Greece:
http://www.ancientgreece.com/

Ancient Greek World: 
http://www.fordham.edu/halsall/ancient/asbook07.html

Ancient History Sourcebook:
http://www.museum.upenn.edu/Greek_World/index2.html

Certamen Questions Database:
http://www.geocities.com/bwduncan/

Latin Dictionary and Grammar Aid:
http://www.nd.edu/~archives/latgramm.htm

Latin Grammar Drills: 
http://www.math.ohio-state.edu/~econrad/lang/latin.html

For Fun: The Weather in Latin:
http://latin.wunderground.com/